United's first win of the pre-season campaign came with a glut of goals at Bramall Lane on Friday night.
Dundee were the visitors but the Blades were impressive as Chris Basham and Marc McNulty netted debut goals.
Jamie Murphy and Jose Baxter were also on target in United's third pre-season outing.
Alcock, McGahey, Basham and Campbell-Ryce all got their first tastes of the Lane as Blades players, starting against the Scottish Premiership side, whilst Butler and McNulty were on the bench.
The Unitedites who made the trip to the Lane were treated to an entertaining start. Howard pushed a long range effort from McGowan around a post before the Blades took the lead on nine minutes. After Baxter's flick on, a back-pass from Benedictus was short and MURPHY stole in, avoiding the goalkeeper before steering home with his left foot.
Moments later a neat move between Baxter and Basham resulted in the latter's shot being pushed away by goalkeeper Letheren and the rebound from Murphy was also close. Reed, on his 17th birthday, fired just wide from 25 yards and Campbell-Ryce's effort was batted away by Letheren.
For Dundee, a shot from Harkins was deflected wide before they levelled. TANKULIC turned well on the edge of the box and his daisy cutter was perfectly placed, just inside the left post. Howard spared Alcock's blushes as Tankulic looked for a second soon after.
As the half progressed the Blades finished the stronger. Murphy's header from Alcock's cross was pushed over by Letheren and, just before the break, the impressive Reed again tried his luck from distance, this time curling just wide.
Again United started well , retaking the lead after 50 minutes. A Harris cross bounced off a Dundee defender perfectly for BASHAM to slide in and direct the ball into the corner of the net, giving Letheren no chance.
Basham then turned provider as United added a third on 65 minutes. A mix up between Letheren and McAlister saw Basham in the clear but he unselfishly laid off to allow BAXTER to tap home into an empty net.
Boss Clough then made a treble change, McNulty handed his debut and the Scottish striker took just two minutes to make an impression. The ball was loose in the box from a Davies corner and McNULTY intelligent flicked the ball home from a yard, despite a crowded goal-line.
Clough made more changes, including bringing on McGinn, who had around a minute up against his brother before Dundee's Paul was substituted. Further changes interrupted the flow of the game but Khan went close to adding a fifth for the Blades.
With six minutes to go KONRAD forced home a second for Dundee from a corner and Tankulic went close with a free-kick but the Scots were unable to threaten United's advantage before referee Naylor's final whistle.
Blades: Howard (Willis 83), Alcock, McGahey (Butler 73), Collins (Khan 77), Harris (Paling 77), Reed (Doyle 67), Basham (Dimaio 77), Scougall (McGinn 73), Campbell-Ryce (Davies 67), Murphy (McNulty 67), Baxter (Porter 73).
Dundee: Letheren, McGinn, Dyer, Benedictus, Konrad, McBride, Thomson, Harkins, Roberts, McGowan, Tankulic.
Subs: Adam, Ferry, McAlister, Dodd, Boyle, Kerr, Wighton.